Sentiment
by kellythefangirl
Summary: "Sentiment is a chemical defect found in the losing side." Just as a new threat begins to show its face in London, a young girl shows up at Baker Street in the middle of the night, a piece of Sherlock's past that even he wasn't aware of, who shifts Sherlock's priorities-or at least, she should.
1. Chapter 1

**Hello! Thank you to anyone who reads this, it'll probably be a weekly update thing... I hope you like it. Oh, and Season 3 spoilers... I warned you. **

The doorbell rang at 3 a.m. on New Year's Eve, and Sherlock was the only one still awake.

More people were there, of course. Mrs. Hudson, asleep downstairs. John, whom Sherlock didn't trust had enough ordination left to get back home, asleep in his old room. But Sherlock was still at the kitchen table, staring frustrated at an unsolved code.

When the doorbell rang, he didn't have any intention of answering it. It wasn't a client, he could tell. He had heard them walk right up to the door and knock—any client lingers, hesitant, for at least a few seconds. That left a very short list of people—Mary, who was home with a three-month-old baby; Mycroft, definitely not out when there were so many stupid people drunk in the streets; and Lestrade, whom he'd just spoken to on the phone and whom was clearly at Scotland Yard.

The doorbell rang again and Sherlock rolled his eyes, sighed and got up to answer it.

"All right, are you drunk or just stupid?" he asked to whoever was outside as he opened the door. He saw a young teenager smirking back at him.

"Neither," she replied. "And what about you?"

"Neither as well," he said. "Good night." He tried to close the door.

The girl stopped it with her foot. He raised an eyebrow at her. "Are you Sherlock Holmes?" she asked him.

He sighed again. "Yes, and it is three in the morning. Good night."

"That doesn't mean anything to you," she said, smirking again. "You were working. Something difficult, I gather, judging by the state of your hair." Sherlock touched his hair subconsciously, and sure enough, he had been nervously running his hands through it.

"Yes, how did you know that?" he asked her.

She smiled, a hint of sarcasm behind the otherwise sincere grin. "The same way I know that Dr. Watson is asleep upstairs and the landlady will be coming out of her flat in 3, 2, 1…"

Mrs. Hudson opened her door, looking in shock out at the hallway. "Is this the hour for visitors?"

"Not at all, Mrs. Hudson. If you would kindly go back to sleep now, that would be wonderful," Sherlock said.

"I hope your hip feels better, Mrs. Hudson," the girl called after her. She turned around to smile warmly at the girl before looking confused and retreating back inside her bedroom. Sherlock looked at her oddly and decided to test her.

"What kind of work was I doing upstairs?" he asked.

"…A code? Am I right?" she asked.

"You hesitated."

"Not as much practice as you, I'm afraid."

"Who are you?" he asked her.

"Deduce who I am," she told him. "Go on."

He sighed and looked at her, really looked. "Single mother the only parental figure in your life. Ran away tonight—mother was alcoholic, verbally abusive, died this morning. Father absent all your life."

"Anything else about my father, Mr. Holmes?" she asked quietly.

"…Was he an addict?" Sherlock asked hesitantly.

"Good," she said, "which addict?"

He blinked at her. "How am I possibly supposed to know that?"

The girl's smirk faded. "My name is Madison," she said. "I'm your daughter."

**Sorry about the soap-opera-ish cliffhanger. I couldn't help myself. Please review or follow, I would like that. *innocent smile* Thanks for reading!**


	2. Chapter 2

**Hi everyone! Thanks so much for reading... I don't own anything... enjoy!**

Sherlock was stunned for exactly one second before rolling his eyes. "I don't have a daughter."

"Not one that you knew about, clearly," she said, sounding almost bitter, "but you do."

"Why am I supposed to believe you?" he asked, narrowing his eyes. "You could be anyone, really."

"But you don't think so, do you?" she asked.

He hesitated. "It's entirely too early and completely irrational to form an opinion at this time."

"Oh, I'm sure. Can I come in?"

"Certainly." He shook his head as she walked past him and up the staircase. Why was he letting her in? He followed her into his flat, closing the door behind them.

Madison sat at the desk, turning the chair to face Sherlock's by the fireplace just as he sat down there. They sat in silence for a few seconds before he asked, "How did you find me?"

"Are you kidding me?" she asked. "I've read John's blog since I was 10. Everyone has since I was 12. It's got your full names and contact information plastered all over it, as well as a link to your website, where I could clearly see the similarities between you and I. I could also see your narcotics history, plain as day. As well as your continuing struggle with nicotine… and some other things…"

"Right, that's enough," he said, getting up quickly.

"Sorry, did that cross a line? Is that where you start hiding?"

"No, John thinks I'm off smoking as well."

Madison smirked. "You should actually read his blog sometimes, you know. He doesn't believe you. And what about that incident back during the Magnussen case… _Shezza_?"

"Okay, you're a crazed fan, please leave my home," Sherlock said, sighing and getting up to go to the table. "So promising as well. Oh, well. Good night."

"You're denying the intrigue of my case, Mr. Holmes," Madison said from her chair.

"Am I?" he asked, rolling his eyes.

"Yes, you are," she said. "Like why I would come here after my mother died. Think about it, Mr. Holmes. What do you happen to do with your time?"

Sherlock walked back into the living room and stared at her. "Are you a client, a fan, or my… daughter?"

"All three, really," she said. "The second one not as much, though. Are you going to help me or not?"

Sherlock sighed. "Why now, at three in the morning? She didn't just die, I gather."

"No, around eight this morning."

"So why wouldn't you come until now?"

"I would attract attention, wouldn't I? You're famous now, Mr. Holmes. A couple cameras could've caught me going inside. Maybe even picked up our conversation."

Sherlock looked at her incredulously. "And a 13-year-old—"

"14-year-old," she corrected him.

"14-year-old girl alone in the middle of the night won't attract attention?"

"Not on New Year's Day. What's one more kid in this crowd? I can disappear in a crowd if I want to."

"Clearly."

She looked at him, raising an eyebrow. "And what is that supposed to mean?"

"You've been hiding what you can do," he said. "Almost all your life. Why?"

"What gave it away?"

"Your eagerness to demonstrate it now."

She sighed. "I suppose you're right. But you know why."

"Of course I do."

"Then why ask me?"

"I want you to prove you know why."

"You don't think I have an understanding of my own psyche?"

"I hope that you do. If you don't, you're definitely not as intelligent as you seem to be."

Madison smiled somewhat bitterly. "Didn't need anyone calling me a freak when Mum already made it quite clear."

"Obviously. Why come here, then? What was so… mysterious about your mother's death?" Sherlock had sat back down. Madison had taken off her coat.

"First of all, she had shown no signs of anything out of the ordinary yesterday," she told him. "Possibly a little more drinking than usual—"

"Alcohol poisoning."

"But it didn't have an affect until she got up, had breakfast, and felt ill a half hour later."

"I still don't see why this requires me."

Madison groaned. "I know it wasn't accidental. I can tell the difference between an accident and a murder. Can't you tell, Mr. Holmes?"

He nodded. "If I'm presented with the evidence. Which I have not been. I don't understand why you wouldn't simply investigate it yourself, since you seem so… proficient at deduction already."

"I don't see why you're so eager to interrogate me as to why I would come to you, I'd end up here eventually anyway," she said.

"Why?"

Madison rolled her eyes. "Mum didn't have a will. I'd be taken to the closest living family member they could find."

"But I'm not in the record books as your father. I'm probably not even your father in the first place. Why are we having this conversation?"

"Because you think I'm right," she said. "Don't you? You can't deny we aren't similar, Mr. Holmes. Not just intellectually either." It was true—Madison had the same dark hair and blue-green eyes. But that didn't prove anything. A few seconds later, Madison sighed. "Ah. We woke Dr. Watson."

"What the hell?" mumbled John, still stumbling slightly, from the end of the hall, where he had just emerged from his old bedroom. "A client? Now?"

"No," Sherlock said. "Well, sort of."

"What do you mean, sort of?" he asked, slurring a little.

"I'm Madison, Dr. Watson," she said. "Sherlock's daughter."

"Unproven as of this minute, but it's a possibility."

John blinked several times. "Right. Still drunk. Going to bed." Sherlock decided it would be best not to argue as John went back to his room. He stood up then and walked into the kitchen.

"I'll take the case. In the morning," he added. "I'm working on the code, I'll have figured it out by then. You can sleep on the couch for tonight."

"That's it?" Madison asked indignantly. "Sleep on the couch, I'll get to you when I'm done?"

"Oh no, that's not it," Sherlock said. "I'll take your case in the morning… after I call Molly."

"Who's Molly? Call her for what?"

He smiled somewhat sarcastically. "To see if you're telling the truth."


	3. Chapter 3

**Next chapter, woo! Okay, well, I don't own anything but I guess Madison... review? :)**

Madison woke up the next morning to see Sherlock, looking as if he hadn't moved from his spot at all. "Did you solve the code?" she asked him.

He looked up. "Ah, you're up. I'll call Molly in a bit."

"You mean after you've solved the code," she said. "Which you haven't yet." Sherlock sighed. "No, I haven't solved it yet."

John walked into the kitchen as Madison came closer to look over his shoulder. "Uhh, have I missed something?"

Sherlock's eyes narrowed in disbelief. "There is no way you were that drunk."

"Apparently I was. All I know is there is a teenage girl I've never seen before in the middle of your kitchen."

"Madison," she said. "I'm his daughter."

John's eyes widened. He looked from Sherlock, to Madison, and back to Sherlock. "Um…what the hell?"

"The validity of that statement is under discussion."

"How the hell… what? You have a daughter?" John asked in shock.

"Really John, I believe you know perfectly well how, you have a daughter yourself," Sherlock said, looking back at the code.

"Is there any kind of key?" Madison asked.

"You really don't think I would have noticed if there was?" he asked her.

She looked at the message herself. It took her less than five minutes to say, "There's a random number and an arrow pointing to the right. It's a Caesar Cipher. Clearly."

Sherlock and John both looked directly at her, amazed, though John considerably more so. "Ah, well, in hindsight, yes, clearly," Sherlock said. Madison looked very pleased with herself.

"I'll call Lestrade," John said, shaking his head. "Try to decipher it."

They did: it showed a complete address on the outer part of town. Lestrade called back twenty minutes later and said that they found the little girl all alone in the building with the address. Madison never stopped looking smug. Finally Sherlock had had enough. "What are you so pleased about?"

"I solved a case before Sherlock Holmes," she said, smiling even wider.

"I'm calling Molly," he said shortly, getting up.

"Do you want anything to eat, Madison?" John asked.

"No, I'm fine." she said. "Not now."

"Okay, Molly's waiting at Bart's, let's go," Sherlock said, and tossed Madison her coat.

* * *

"Hello, Molly," he said when they got to hospital. "I need you to run some tests."

"Okay, why? And who's this?" she asked, looking confused.

"This is Madison," Sherlock said. "I want you to do a paternity test."

"Sorry?" Molly asked, looking even more confused. "But you don't—I mean, you haven't—have you?—how even would—"

"Molly, please," he said, no longer looking at her.

"O-okay," Molly said quietly.

Twenty minutes later, she came out of her lab. "Well?" Madison asked.

She bit her lip. "What the hell even happened, Sherlock? And why did you never tell me?" she asked.

"What do you—"

"She's your daughter, all right. How?" Molly repeated.

"Ah, when I was younger, I had a less-than-intelligent lifestyle."

"I know that, Sherlock," she said. "Did you not even know? Never mind, I know you didn't, but… how did you not even know?"

"It's him," Madison said bitterly. "He doesn't care about anything, no matter what it is. He didn't know my mum's name, much less that I existed."

"Then how did you find him, Madison?" Molly asked.

"She, ah, takes after me, shall we say," Sherlock said.

"Oh, dear God," Molly moaned. "Are you sure?"

"She's back together with her boyfriend—they started over, so not engaged, but together," Madison told Sherlock.

"I realize that. I was attempting manners."

Madison shrugged. "She doubted me. I proved it. Who cares about manners?"'

"You're enjoying us not thinking it's strange a little more than you should be."

"Thank you for the psychoanalysis, Sherlock," Madison sighed.

"First name basis?" Molly asked, sounding a little disapproving.

"For God's sake, he didn't even know my first name until 8 hours ago. I have to be respectful?" Madison asked.

"So what happens now?" Molly asked.

Sherlock sighed. "Mother dead, I'm officially her father now, I'm not convicted of crimes and I'm of… well, legally sound mind."

"So?"

He looked over at Madison, then back at Molly. "She moves in."


End file.
